This invention relates to method and apparatus for measuring the temperature of surfaces, and more particularly to the inside surfaces of an operating furnace.
There exists a need for a reliable, accurate means for measuring temperature profiles inside furnaces to monitor furnace performance and to optimize furnace operation. It is desirable that these temperature measurements be spatially resolved. Economic and environmental concerns make it critical that furnaces used in applications such as waste remediation and industrial processes be efficient with little or no hazardous emissions. Knowledge of the internal spatial temperature distribution within such a furnace is a key parameter for monitoring furnace performance and is necessary for furnace optimization.
Present temperature measurement instruments have a number of shortcomings that make them unreliable, inaccurate, or hazardous for use inside the hot, hostile environment of furnaces. For example, infrared pyrometers cannot view through smokey, hazy, and/or particle filled off-gases, their view can be further blocked by deposits on exposed viewing windows, and knowledge of surface emissivity is required to accurately interpret temperature. Other temperature sensors such as thermocouples require electrical wires being brought into the furnace which have a limited high temperature capability, are prone to failure and, would be a hazard in electric furnace applications.